sh: test: argument expected

[Steve Holden]

Iván Cabria wrote:

> Hi,
> 
> I am a new user of python. I ran 
> a python script and I got the 
> following message:
> 
> sh: test: argument expected
> 
> I found that this error came from a 
> line in the script:
> energy = atoms.GetPotentialEnergy()
> 
> I looked for a solution to this 
> problem in Internet and I found  
> (http://www.experts-exchange.com/Operating_Systems/Unix/Q_20706303.html)
> that the problem was that the variable 
> was not initialised. I also found 
> that the bash shell initialises the variables 
> automatically and the Bourne shell (sh) does not.
> (http://www.experts-exchange.com/Operating_Systems/Unix/Q_20706303.html)
> 
> I suppose that 'sh:' in the error message 
> means that the script is using the Bourne shell, 
> and hence, I understand the message error.
> 
> However, I was using the bash shell in the computer 
> I ran the script, not 
> the Bourne shell (sh). Hence, I do not 
> understand the 'sh:' in the error message.
> Could be that python scripts are using by default the 
> Bourne shell?
> 
> The first line of the python script is:
> #!/usr/bin/env python
> 
> Thanks in advance.
> 
> 
Question 1: if you run the script using "python scriptname.py" does the 
error go away? If so then your script is being executed by the shell and 
not by the python interpreter.

Question 2: Are there any blank lines or empty spaces before
#!/usr/bin/env python ?

regards
  Steve
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